create global variables?



J. Clifford Dyer wrote:
Alistair King wrote:

Hi,

is there a simple way of creating global variables within a function?

ive tried simply adding the variables in:

def function(atom, Xaa, Xab):
Xaa = onefunction(atom)
Xab = anotherfunction(atom)

if i can give something like:

function('C') #where atom = 'C' but not necessarly include Xaa or Xab

i would like to recieve:

Caa = a float
Cab = another float

ive tried predefining Xaa and Xab before the function but they are
global values and wont change within my function. Is there a simple way
round this, even if i call the function with the variables ('C', Caa, Cab)?

................................................................................................................................

some actual code:

# sample dictionaries
DS1v = {'C': 6}
pt = {'C': 12.0107}

def monoVarcalc(atom):
a = atom + 'aa'
Xaa = a.strip('\'')
m = atom + 'ma'
Xma = m.strip('\'')
Xaa = DS1v.get(atom)
Xma = pt.get(atom)
print Xma
print Xaa

monoVarcalc('C')

print Caa
print Cma

................................................................................................................................
it seems to work but again i can only print the values of Xma and Xaa

?

Alistair



I suspect you are misusing the concept of a function. In most basic
cases, and I suspect your case applies just as well as most, a function
should take arguments and return results, with no other communication
between the calling code and the function itself. When you are inside
your function don't worry about the names of the variables outside. I'm
not sure exactly where your floats are coming from, but try something
like this:

>>> def monoVarCalc(relevant_data):
... float1 = relevant_data * 42.0
... float2 = relevant_data / 23.0
... return float1, float2

>>> C = 2001
>>> Caa, Cab = monoVarCalc(C)
>>> Caa
84042.0
>>> Cab
87.0

Notice that you don't need to use the variable C (or much less the
string "C", inside monoVarCalc at all. It gets bound to the name
relevant_data instead.

Also, if you are going to have a lot of these little results lying
around, (Cab, Cac ... Czy, Czz), you might consider making them a list
or a dictionary instead. I won't tell you how to do that, though. The
online tutorial has plenty of information on that.

http://docs.python.org/tut/tut.html


Cheers,
Cliff

this worked a treat:

def monoVarcalc(atom):

a = atom + 'aa'
Xaa = a.strip('\'')
m = atom + 'ma'
Xma = m.strip('\'')
Xaa = DS1v.get(atom)
Xma = pt.get(atom)
return Xaa, Xma


Caa, Cma = monoVarcalc('C')


thanks

Ali

--
Dr. Alistair King
Research Chemist,
Laboratory of Organic Chemistry,
Department of Chemistry,
Faculty of Science
P.O. Box 55 (A.I. Virtasen aukio 1)
FIN-00014 University of Helsinki
Tel. +358 9 191 50392, Mobile +358 (0)50 5279446
Fax +358 9 191 50366



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